From 2eceba39a59bd0ec34e0ae4ea108a40e33c159ed Mon Sep 17 00:00:00 2001
From: Nikolaus Schuetz <nikolauspschuetz@gmail.com>
Date: Tue, 21 Jul 2026 23:18:05 -0700
Subject: [PATCH] fix: accept memoryview in decode and decode_lazy

rlp.decode rejected memoryview objects (is_bytes only accepts bytes and
bytearray), and rlp.decode_lazy raised a TypeError because the lazy codec
concatenates slices of the input (memoryview does not support +).

Normalize a memoryview input to bytes at the top of both entry points,
mirroring the existing bytearray handling, so memoryview is a first-class
input like bytearray.

Closes #115
---
 rlp/codec.py                  |  3 +++
 rlp/lazy.py                   |  3 +++
 tests/core/test_memoryview.py | 24 ++++++++++++++++++++++++
 3 files changed, 30 insertions(+)
 create mode 100644 tests/core/test_memoryview.py

diff --git a/rlp/codec.py b/rlp/codec.py
index 63386fe..d9a5b8c 100644
--- a/rlp/codec.py
+++ b/rlp/codec.py
@@ -290,6 +290,9 @@ def decode(rlp, sedes=None, strict=True, recursive_cache=False, **kwargs):
              item and `strict` is true
     :raises: :exc:`rlp.DeserializationError` if the deserialization fails
     """
+    if isinstance(rlp, memoryview):
+        rlp = bytes(rlp)
+
     if not is_bytes(rlp):
         raise DecodingError(
             "Can only decode RLP bytes, got type %s" % type(rlp).__name__, rlp
diff --git a/rlp/lazy.py b/rlp/lazy.py
index 170bcc2..7a720cd 100644
--- a/rlp/lazy.py
+++ b/rlp/lazy.py
@@ -39,6 +39,9 @@ def decode_lazy(rlp, sedes=None, **sedes_kwargs):
     :returns: either the already decoded and deserialized object (if encoded as
               a string) or an instance of :class:`rlp.LazyList`
     """
+    if isinstance(rlp, memoryview):
+        rlp = bytes(rlp)
+
     item, end = consume_item_lazy(rlp, 0)
     if end != len(rlp):
         raise DecodingError("RLP length prefix announced wrong length", rlp)
diff --git a/tests/core/test_memoryview.py b/tests/core/test_memoryview.py
new file mode 100644
index 0000000..c22f20c
--- /dev/null
+++ b/tests/core/test_memoryview.py
@@ -0,0 +1,24 @@
+from rlp import (
+    decode,
+    decode_lazy,
+    encode,
+)
+
+
+def test_memoryview():
+    e = encode(b"abc")
+    expected = decode(e)
+    actual = decode(memoryview(e))
+    assert actual == expected
+
+
+def test_memoryview_lazy():
+    e = encode(b"abc")
+    expected = decode(e)
+    actual = decode_lazy(memoryview(e))
+    assert expected == actual
+
+
+def test_memoryview_nested_list():
+    e = encode([b"cat", b"dog", [b"nested", b""]])
+    assert decode(memoryview(e)) == decode(e)